Sheet handling device for printing machines



June 13, 1961 A. w. RANGER 2,988,357

SHEET HANDLING DEVICE FOR PRINTING MACHINES INVENTOA Arthur WillardRanger Attorney June 13, 1961 w, RANGER 2,988,357

SHEET HANDLING DEVICE FOR PRINTING MACHINES Filed Dec. 51, 1958 llSheets-Sheet 2 //VV N709.

Arthur Willard Ranger ttor'ney A. W. RANGER SHEET HANDLING DEVICE FORPRINTING MACHINES June 13, 1961 ll Sheets-Sheet 3 Filed Dec. 31, 1958//VV/W'0AZ' Arthur Willard Rang-er Attorney 7 5 3, oo 8 w 2 June 13,1961 A. w. RANGER SHEET HANDLING DEVICE FOR PRINTING MACHINES llSheets-Sheet 4 Filed Dec. 31, 1958 /A/V/\'/r0/2.- Arthur Willa d Bangerttor'ney June 13, 1961 A. w. RANGER SHEET HANDLING DEVICE FOR PRINTINGMACHINES Filed Dec. 31, 1958 ll Sheets-Sheet 5 /Nl/N70A Arthur WillardRange Verne:-

June 13, 1961 A. w. RANGER 2,988,357

SHEET HANDLING DEVICE FOR PRINTING MACHINES Filed Dec. 51, 1958 11Sheets-Shee't a Arthur Willard nger torney June 13, 1961 A. w. RANGERSHEET HANDLING DEVICE FOR PRINTING MACHINES Filed Dec. 31, 1958 11Sheets-Sheet 7 //VI/N70/?-' Arthur Hillard Ranger Attorney June 13, 1961A. w. RANGER SHEET HANDLING DEVICE FOR PRINTING MACHINES Filed Dec. a1,1958 ll Sheets-Sheet 8 //v1//vr0A llard Earlier Arthur W1 J1me 1961 A.w. RANGER 2,988,357

SHEET HANDLING DEVICE FOR PRINTING MACHINES Filed Dec. 51, 1958 llSheets-Sheet 9 Arth Hi ard Ran y A f June 13, 1961 A. w. RANGER SHEETHANDLING DEVICE FOR PRINTING MACHINES Filed Dec. 31, 1958 llSheets-Sheet 1O Attorney June 13, 1961 A. w. RANGER SHEET HANDLINGDEVICE FOR PRINTING MACHINES 11 Sheets-Sheet 11 Filed Dec. 51, 1958//Vl/N7'0A Arthur Willard ger Attorney swat 2,988,357 SHEET HANDLINGDEVICE FOR PRINTING MACHINES Arthur Willard Ranger, Brighton, England,assignor to Schnellpressenfabrilr Aktiengesellschaft Heidelberg,Heidelberg, Germany Filed Dec. 31, 1958, Ser. No. 784,118 '(llaimspriority, application Great Britain Jan. 6, 1958 7 Claims. (Cl. 271-82)This invention relates to a gripper device, which although primarilyintended for application to sheet-fed printing machines can also beapplied to other sheet-fed paper or other sheet handling machines (suchas diecutting, bronzing, folding or like machines whether for paper ormetal sheets). It is applicable to printing machines of the sheet-fedcontinuously rotating cylinder type; and it is also applicable toauxiliary feeder drums and/ or to cylinders feeding sheets tocontinuously rotating cylinders. The invention has as its object theprovision of means for ensuring the correct registration of sheets whenthey are seized by the cylinder grippers.

In most continuously rotating cylinder machines, of both one and tworevolution types, the sheet to be printed is taken from a stationaryposition on a feedboard by grippers mounted within the cylinder. Thegrippers close on the sheet at the moment of gripping and nip it againstthe leading edge of the cylinder as it rotates beneath the feed-board.The actual gripping action 'is that of a snatch at the sheet and it willbe appreciated that any material change of speed is liable to result ina variation of sheet register, which register is essential for goodquality work and especially in color work. With .color work it isusually necessary to run the machine at a substantially uniform speedthroughout the printing of any given color and this has an adverseeffect on production.

An additional disadvantage of the snatching action is that the frontlays registering the sheet have to lift as the grippers seize the sheetin order to avoid fouling the front edge of the sheet as it is pulledforward at high speed onto the cylinder. Lifting of the lays leaves thesheet momentarily out of control and to maintain control drop fingersmay be provided which fall onto and steady the sheet at the moment oftransference. These fingers however frequently vibrate at high speedsand form an obstruction to the machine minder.

With high speed machines where accuracy of registration is consideredessential recourse may be had to an auxiliary gripper system which ismounted on the machine frame and grips the stationary sheet, swinging itforward to transfer it to the cylinder grippers at cylinder speed. Suchauxiliary grippers not only add appreciably to the cost of the machinebut ofier considerable obstruction to the machine minder when makingready.

In order to overcome the disadvantage due to the snatching actionreferred to, it was proposed in the specification of British Patent No.507,522 to carry the grip per shaft and the abutment bar on arms mountedon a rocking shaft carried between the end Walls of the cylindereccentrically of the cylinder shaft and to provide a cam surfaceexternal to the cylinder sensed by a roller carried by a lever on theend of the shaft for the purpose of rocking the arms whereby theabutment bar would be stationary or very slowly moving as the grippersclosed to grip a sheet, the abutment bar and grippers thereafteraccelerating until they travelled at cylinder speed. With such anarrangement, at high speeds of rotation of the cylinder, strong springshad to be employed to maintain vibration-free sensing of the cam surfaceby the roller. resulting in rapid wear which in turn caused undesirablevibration between the grippers and abutment bar.

2,988,357 Patented June 13, 1961 An object of the present invention isto ensure that the operation of the rocking shaft and gripper shaftshall be such that not only is the abutment bar substantially stationarywhen brought to the leading edge or lays of the feed-board and as thegrippers close onto the sheet, but the abutment bar and grippers arepositively controlled as they approach the sheet gripping position andremain so positively controlled until they have seized the sheetirrespective of the rotational speed of the cylinder.

A sheet handling machine having a lay board to which sheets aredelivered individually and successively, according to the presentinvention, comprises in combination, a rotatably driven, hollow cylinderformed with a longitudinally extending opening, a rockable first shaftextending longitudinally of the cylinder internally thereof andprojecting outwardly at at least one end of the cylinder, a second shaftcarried by the first shaft, grippers on said second shaft, abutmentmeans adapted to coact with said grippers for transferring a sheet fromthe lay board to the cylinder and fixed relative to said first shaft toform together with said second shaft and said grippers a rock able unit,control member means mounted on the first rockable shaft externally ofthe cylinder, first. and second fixed pins adapted to co-operatesuccessively during rotation of the cylinder with said control membermeans to elfect rocking movement of said rockable unit from a firstposition in which the abutment means are disposed within the cylinder toa second position angularly spaced from the first postion in which theabutment means project through said longitudinally extending opening inthe cylinder and substantially coincide with the plane of a sheet on thelay board, means operable to effect opening of the grippers at saidfirst position, and means operable to efiect closure of the grippers atsaid second position, whereby at said second position of the rockableunit, the abutments means, the axis of the second pin co-opcrating withthe control member means and the axis of the first shaft are disposedsubstantially in a. radial plane relative to the axis of the cylinderthereby to preclude any substantial relative movement between a sheetrcgistered and aligned on the abutment means irrespective of therotational speed of the cylinder.

Preferably, the control member means are adapted so to coact with thesecond fixed pin that over a few degrees of rotation of the cylindersubsequent to said. second position of the rockable unit, the abutmentmeans at locations thereof engaged by the grippers remain substantiallystationary.

'In the accompanying drawings illustrating examples of the invention;

FIG. 1 is a somewhat diagrammatic side sectional elevation showing therelative positions of the various parts as the grippers have gripped asheet;

FIG. 2 is a plan of FIG. 1;

FIGS. 3 to 6 are diagrammatic side sectional elevations of part of thecylinder showing the relative positions of the tumbler and grippers atsuccessive points of rotation of the cylinder. The slotted lever and pinfor operating the grippers have been omitted for clarity.

FIG. 3 shows the position of the cylinder just before delivery of aprinted sheet, and with the tumbler about to engage the opening pin;

FIG. 4 shows the tumbler about to engage the closing pin, with thegrippers open ready to grip a sheet;

FIG. 5 shows the moment of sheet gripping by the grippers, the lays arestationary and although the cylinder is moving, the grippers andabutment bar are also sub stantially stationary;

FIG. 6 shows the sheet being drawn from the lay board, the lays havebeen lifted and the abutment bar has closed onto the cylinder nose;

FIG. 7 is a diagram showing the position of the abutment in relation tothe sheet edge during the period of pp FIGS. 8 and 9 are respectively adiagrammatic side and front elevation of means for maintainingregistration when the cylinder of a single or two revolution machine islifted;

FIG. 10 is a detailed view in side elevation of a combined packing clampand rocking unit opening device;

FIG. 10A is a plan view thereof;

FIGS. 11 to 14 are sectional side elevations of a modified tumbler andgripper control;

FIG. 11 shows the grippers open and approaching the lay board to grip asheet;

FIG. 12 shows a sheet being gripped by the grippers;

FIG. 13 shows the sheet being drawn off the lay board;

FIG. 14 shows the point of delivery of a printed sheet;

FIG. 15 is a side sectional elevation showing the relative position ofthe parts carried by the cylinder when a sheet has been gripped.

FIG. 16 is a plan view on FIG. 13; and

FIG. 17 is a side elevational detail of a packing clamp opening device.

FIG. 18 is a side sectional elevation showing an alternative arrangementfor operating the rocking gripper unit.

In the example of a printing machine shown in FIGS. 1 to 10A, acylinder, generally designated 1 is carried by a shaft 2 mounted inhearings in the side frame 3 of the printing machine.

A rocking shaft 4 mounted in bearings in the end walls 12 of thecylinder has a number of arms 5 spaced along it (only one of which isshown) secured to it as by pins 6. The arms 5 carry a gripper shaft 7and an abutment bar 8. A number of grippers 9 are mounted on the grippershaft 7. The grippers may be fixed or adjustably mounted.

Secured to at one or each end of the gripper shaft 7 is a curved lever10 having an arcuate open-ended slot 11 therein, the lever 16 beingadjacent the end Wall 12 of the cylinder.

The curved slotted lever 10 engages a pin 13 on the cylinder wall toeffect the opening and closing of the grippers, imparting thereby apositive action to the grippers eliminating vibration and faulty closingof the grippers onto a sheet as hereinafter explained.

A helical spring 14, wound around the gripper shaft 7 is anchored at oneend 15 to the abutment bar 8 and is anchored at the other end 16 under agripper 9. The spring 14 keeps the grippers closed when they are notunder the control of the slotted lever 10.

One end of the rocking shaft 4 passes through the end wall 12 of thecylinder and has secured thereto a tumbler 22.

The tumbler 22 is slotted at both ends for engagement respectively andsuccessively with opening and closing pins 23, 24, mounted on the sideframe 3 of the machine.

Although in the foregoing description the tumbler and its associatedpins are described as being at one end of the cylinder, if desired asecond tumbler and associated pins may be arranged at the other end ofthe rocking shaft, which would, of course, be extended to pass throughthat end wall.

Pivotally mounted on the arm 5 by a pivot pin 21 is a rod 17, the end 18of which passes through a lug 19 secured to the end Wall of thecylinder. A helical spring '20 is interposed between the lug l9 and thehead on the rod receiving the pivot pin 21 and is under compression. Theobject of the spring is to hold the tumbler 22 in either of its twoextreme positions against stops 25, 26 mounted in the cylinder wall 12,after engagement with the pins 23, 24, in order to prevent undesirableoscillation of the rocking shaft 4 and tumbler 22.

As long as either of the parallel portions of the slotted ends of thetumbler 22 is in engagement with its 4 appropriate pin 23, 24 therocking shaft 4 is positively controlled irrespective of the speed ofthe cylinder.

The abutment bar 8 is preferably machined from a solid bar. It hasknurled abutment surfaces or gripping faces 27 at intervals along it andrecesses (which are not shown) to provide a clearance for packing clamps28 and to allow clearance for the delivery mechanism, not shown.

The packing clamps 28 are mounted on a packing clamp shaft 29, which isrotated by the mechanism shown in FIGS. 10 and 10A. The clamp shaft 29projects from one end wall 1 2 of the cylinder and has secured thereto alever 30 provided with a slot 31 into which fits a stud 32 secured to anarm 33 pivotally mounted on a pin 34 in the end wall of the cylinder. Ahole 35 is provided in the arm 33 for a tomnty bar or the like wherebyleverage may be exerted on the arm 33, causing the stud 32 to bearagainst one wall of the slot 31 rocking the lever 30 and with it theclamp shaft 29. To lock the clamps in the open position, the lever 30 isprovided with an armate recess 36 into which a roller 37 engages whenthe arm 33 has been swung in a counter clockwise direction, FIG. 10. Theroller 37 is carried on a member 38 se cured to the rocking shaft 4. Asthe rocking shaft 4 is spring loaded, it will lock the clamp shaft 29 inthe open position for the clamps.

In the event of the machine minder failing to close the packing clamps28 before starting the machine, a stud, not shown, may be provided onthe side wall of the machine against which the arm 33 will engage as thecylinder rotates, rocking the arm about its pivot pin and swinging thelever 30 to rock the clamp shaft 29 thereby closing the packing clamps,and permitting the abutment unit to take up its normal position adjacentthe cylinder nose.

As illustrated in FIGS. 8 and 9, lays (not shown) carried on a lay shaft40a, co-operate with a lay board 39.

The lays remain at register position until the grippers have closed onthe sheet and are thereafter moved to keep clear of the sheet as thesheet is drawn from the lay board.

A cam surface 41 is secured to the side wall of the machine adjacent thedelivery point for the printed sheet. The cam surface 41 acts to openthe grippers 9. The stud 26 projects inwardly through the end wall ofthe cylinder and has pivotally mounted thereon a bell crank lever 42.One arm 4-3 of this lever carries at its outer end a roller 48, theother arm 44 having an abutment pad 45 near its end. A block 46 housesone end of a compression spring 47 which bears at its other end againstthe arm 43 to rock it clockwise as viewed in FIG. 1. The arm 44 abutsagainst the block 46 and limits clockwise movement.

Because the roller 48 is normally projecting beyond the periphery of thecylinder it will engage the cam surface 41 and be forced inwardly,rocking the bell crank lever 42 against the action of the spring 47. Atthe sametime the abutment pad 45 will bear against the curved lever 10causing the gripper shaft 7 to rock and thereby opening the grippers sothat the printed sheet can be removed by the known delivery mechanism.

In the operation of the grippers in gripping a sheet for printing asshown sequentially in FIGS. 3 to 6 it will be assumed that a printedsheet is about to be delivered, FIG. 3, and that rotation of thecylinder has brought the tumbler 22 with its inner slotted end almostinto engagement with the opening pin 23. Continued rotation of thecylinder swings the tumbler with the rocking shaft as shown in FIG. 4where the outer slotted end is about to engage the closing pin 24. Itwill be observed thatof the spring 20, indicated by the center line. Asthe" aesassr tumbler is rotated under the influence of the opening pin23, the spring 20 will be compressed and move over center so that as thetumbler leaves the pin 23 it will be swung against the stop 25 toposition it to receive the closing pin 24. In the position shown in FIG.4 the grippers have been opened in preparation for the gripping of thesheet.

In FIG. 5 gripping of a sheet has beeneffected. In this position thegrippers are locked against. movement and are under the. completecontrol of the slotted lever and pin 13 (see FIG. 1). When the pin 24 isat the bottom of the slot in the tumbler 22 the axes of the pin 24,rocking shaft 4 and the abutment face are all in a radlal plane passingthrough the center line or axis of the cylinder, this line alsointersecting the plane of the sheet near the lay edge.

At this moment the abutment bar 8 is substantially stationary and theco-operation of the slotted lever 10 and pin 13, as shown in FIG. 1, hascompleted the closing of the grippers 9, which are also stationary,.that is, there is no appreciable relative longitudinal movement betweenthe registered sheet on the .lay board and the grippers and theirabutments, so that correct registrationis maintained.

The grippers and the tumbler are positively held in this positionirrespective of the speed of the cylinder. This condition issubstantially maintained during a few degrees of movement of thecylinder, as shown in FIG- 7, in which A represents the axis of thecylinder, and B the point at which the plane of the sheet intersects thecenter of the control pin 24. F is the center of the abutment face andremains practically stationary atpoint B during the movement of therocking shaft center from C to E. The grippers close during period C toD, while the lays are lifted at a point between D and E, Dbeing on aradial line from A to B.

On continued rotation of the cylinder the sheet is drawn smoothly fromthe lay board at gradually increasing speed to the cylinder nose asshown in FIG. 6.

The pins 23, 24 and the lay bar 40a may be so connected to the mainbearings of the cylinder that they rise and fall therewith, as shown inFIGS. 8 and 9. Stirrup blocks 50 are secured to these bearings at eachside of the cylinder, and these blocks carry the pins 23, 24 and the laybar 40a in their appropriate positions. A cross-shaft 49 supports thelay edge of the hinged feed-board in known manner. When the cylinder israised or tripped so as to clear the form, the registering elements willbe maintained in their correct relative positions so that register isnot affected.

FIGS. 11 to 18 show an alternative construction of the invention inwhich a tumbler 60, mounted on a rocking shaft 61 protruding throughboth end walls 62 of the cylinder, is provided with a roller 63 forengaging a cam track 64 as hereinafter described.

As in the previous example opening and closing pins, respectively 65, 66are secured to the side frame 67 of the machine.

Secured to the rocking shaft 61 are arms 68 carrying at their outer endsan abutment bar 69. A gripper shaft 70 is carried in bearings in thearms 68 'and secured to the gripper shaft 70 are a plurality of grippers71. One of the grippers, adjacent an end wall of the cylinder isprovided with an arm 72 on which is mounted a roller 73 for engaging acam track 74, secured to the side of the machine frame. Abutment by theroller 73 on the cam track 74 rocks the gripper shaft 70 to release aprinted sheet as hereinafter. described.

Another gripper, at the end of the gripper shaft remote from the grippercarrying the roller 73, has secured to or integrally formed therewith aslotted lever 75 which is adapted to be engaged by a stud 76 during partof a printing cycle. The stud 76 is secured to an end wall of thecylinder.

Both the gripper shaft 70 and rocking shaft .61 are spring loaded. Thegripper shaft 70 has an encircling spring 78 tensioned to rock thegripper shaft 70 to urge the grippers against the abutment bar 69, andthe rocking shaft 61 has an encircling spring 79, anchored at one end toa bearing lug 80 through which the rocking shaft passes, tensioned torock the rocking shaft to urge the arms 68, and hence the abutment bar69 adjacent to the cylinder nose against a suitable stop 91.

As shown in FIGS. 16 and 17, unlocking means for the packing clamps 81comprise a bell crankv lever secured to the packing clamp shaft 82, oneend 8 3 of the bell crank lever acting as a manually operated lever forrock.- ing the packing clamp shaft, the other arm 84 of the bell cranklever having an arcuate recess 85 near its end. for the reception, whenthe packing clamps are in the opened position, of a stud 86 on a member87 secured to the end of the rocking shaft 61 projecting beyond. thecylinder wall.

As the rocking shaft 61 is spring urged in a clockwise direction, FIG.17, engagement of the stud 86 in the arenate recess 85 will lock thepacking clamps in the open position.

To avoid possible damage to the machine by accidental operation when thepacking clamps are open, an abutment 88, secured to the side frame ofthe machine is positioned in the path of the arm 83 when in the clampsopen position, and continued rotation of the cylinder once the arm 83has struck the abutment 88 will force the arm towards the cylindersurface, unlatching the stud 86 from the arcuate recess 85 and therebyautomatically closing the packing clamps, and the rocking shaft underthe influence of its spring will re-asume its normal position.

The stop 91 on the cylinder end wall prevents the tumbler swinging orvibrating when the pin '65 is entering the tumbler and during a printingoperation.

The sequence of events during a printing cycle closely follows that ofthe previous example. The action of the stud 7 6 in relation to theopening of the grippers at differ-i ent stages of cylinder revolutionbeing shown, itwill be understood that a very similar action takesplacein the example previously described with reference to the slottedlever 10 and pin 13, although their relative positions are not shown inFIGS. 3 m6 Referring to FIGS. 11 to 14, which show details of a printingcycle. In FIG. 11 the tumbler 60 is in contact with both opening andclosing pins 65, 66, leaving pin 65 and just entering pin66;Transference from one pinto the other is effected smoothly.

It will be appreciated that, in the previous example,- the pins 23, 24and the tumbler 22 and spring-20 mayalso be so positioned andproportioned that the transfer until the slotted outer end of thetumbler fully engagesthe closing pin 66, as shown in FIG. 12. At thepoint shown in FIG. 12 relative motion is taking place between thetumbler and the cylinder, rocking the rocking shaft 61 in a directionopposite to that of the cylinder, thereby ensuring that the grippers andabutment bar are substantially stationary during the time the grippersclose on the sheet. A sheet is shown in FIG. 12 just after gripping bythe grippers. The stud 76 is still controlling the slotted lever 75preventing thereby any vibration of the grippers as they close onto thesheet.

Continued rotation of the cylinder will cause the tumbler 60 to continueto rotate under the influence of the closing pin 66, the rockingmovement swinging the tumbler round until the roller 63 engages the camtrack 64. At the point Where the cam track is left by the.

roller, the rocking shaft 61 has rotated the gripper as- I semblage,namely grippers and abutment bar, so that they nestle adjacent thecylinder nose. As shown in FIG. 13, the sheet 90 is being drawn from thelay board or transfer machine smoothly by the grippers which are nowheld closed by the spring 78.

Between the positions shown in FIGS. 12 and 13, the grippers willcommence to move from their stationary position and will accelerateuntil they are nestled adjacent the cylinder nose when they will bemoving with the cylinder at cylinder speed.

During the printing period the tumbler will abut against the stop 91.

In FIG. 14 the sheet delivery position is shown. The tumbler is steadiedby the opening pin 65 and the gripper shaft 70 is rocked by the roller73 riding under the cam track 74 opening the grippers so that theprinted sheet can be removed from the cylinder.

The slotted lever 75 is not in engagement with the stud 76 and thegripper shaft 70 is free to rock under the cam action of the cam track74.

It will be appreciated that as the printed sheet is peeled from thecylinder while the latter rotates, so the tumbler is swung about therocking shaft 61 by the opening pin 65, into the position shown in FIG.11 in preparation for another sheet gripping operation.

Instead of the roller '63 on the tumbler 6t) engaging the cam track 64,the tumbler may be provided with a cam track for engaging a rollermounted on the side frame of the machine.

As shown in FIG. 18, the gripper unit shaft 61 may be rocked by means ofa secondary shaft 61a on the end of which is mounted the tumbler 60carrying the roller 63. Levers 92 on the shaft 61 are connected by links93 and pins 94, 95 to the upper limb of the tumbler 60. The opening andclosing pins 65, 66 are suitably positioned to effect co-operation withthe upper and lower slots of the tumbler 60 as previously described, andresultant rocking of the secondary shaft 61a will produce like rockingof the gripper unit to effect gripping and transport of the sheet. Theroller 63 and cam 64 will complete the rocking movement of the gripperunit as already described.

In the appended claims the expression sheet handling machine is used asmeaning a machine for handling sheets of paper or other material whichare fed to it and includes any printing or other sheet handling machine(such as die-cutting, bronzing, folding, or like machines whether forpaper or metal sheets), which include a cylinder which may be a printingcylinder or a transfer cylinder provided with a gripper device forgripping the paper.

What I claim is:

1. A sheet handling machine having a lay board to which sheets aredelivered individually and successively, comprising in combination, arotatably driven, hollow cylinder formed with a longitudinally extendingopening, a rockable first shaft extending longitudinally of the cylinderinternally thereof and projecting outwardly at at least one end of thecylinder, a second shaft carried by the first shaft, grippers on saidsecond shaft, abutment means adapted to coact with said grippers fortransferring a sheet from the lay board to the cylinder and fixedrelative to said first shaft to form together with said second shaft andsaid grippers a rockable unit, con trol member means mounted on thefirst rockable shaft externally of the cylinder, first and second fixedpins adapted to co-operate successively during rotation of the cylinderwith said control member means to effect rocking movement of saidrockable unit from a first position in which the abutment means aredisposed within the cylinder to a second position angularly spaced fromthe first position in which the abutment means project through saidlongitudinally extending opening in the cylinder and substantiallycoincide with the plane of a sheet on the lay board, means operable toeffect opening of the grippers at said first position, and meansoperable to effect closure of the grippers at said second position,whereby at said second position of the rockable unit, the abutmentmeans, the axis of the second pin co-operating with the control membermeans and the axis of the first shaft are disposed substantially in aradial plane relative to the axis of the cylinder thereby to precludeany substantial relative movement between a sheet registered and alignedon the abutment means irrespective of the rotational speed of thecylinder.

2. A sheet handling machine according to claim 1, in which the controlmember means are adapted so to coact with the second fixed pin that overa few degrees of rotation of the cylinder subsequent to said secondposition of the rockable unit, the abutment means at locations thereofengaged by the grippers remain substantially stationary.

3. A sheet handling machine according to claim 1, in whch the axis ofthe second pin is disposed in a radial plane of the cylinderapproximately corresponding to a radial plane of the cylinder in whichthe leading edge of an individual sheet is disposed when in registeredposition on the lay board.

4. A sheet handling machine according to claim 1, in which the meansoperable to effect closure of the grippers at said second position ofthe rockable unit comprise a lever member mounted near an end of saidsecond shaft and formed with a curved slot and a complementary pinmounted on an end of the cylinder and adapted to engage within said slotso that, during rocking of the rockable unit to the second positionthereof, co-operation between said slot of the lever member and saidcomplementary pin effects closure of the grippers.

5. A sheet handling machine having a lay board to which sheets aredelivered individually and successively, comprising in combination, arotatably driven, hollow cylinder formed with a longitudinally extendingopening, a rockable first shaft extending longitudinally of the cylinderinternally thereof and projecting outwardly at at least one end of thecylinder, a second shaft carried on the first shaft, grippers on saidsecond shaft, abutment means adapted to coact with said grippers fortransferring a sheet from the lay board to the cylinder and fixedrelative to said first shaft to form together with said second shaft andsaid grippers a rockable unit, control member means comprising a leverarm formed with slots extending inwardly'from respective opposite endsthereof and rotatably mounted on said first shaft externally of thecylinder, first and second fixed pins mutually spaced angularly relativeto the axis of the cylinder and adapted to co-operate successively,during rotation of the cylinder, with respective slots of said lever armto effect rocking movement of said rockable unit from a first positionin which the abutment means are disposed within the cylinder to a secondposition in which the abutment means project through said longitudinallyextending opening in the cylinder and substantially coincide with theplane of a sheet on the lay board, and means operable to effect openingof the grippers at said first position of the rockable unit, there beingfurther provided a lever member mounted near an end of said second shaftand formed with a curved slot and complementary pin mounted on an end ofthe cylinder and adapted to engage within said slot so that, duringrocking of the rockable unit to the second position thereof,co-operation between said slot of the lever member and saidcomplementary pin effects closure of the grippers, the arrangement beingsuch that, at said second position of the rockable unit, the abutmentmeans, the axis of the second pin co-operating with the control membersmeans and the axis of the first shaft are disposed substantially in aradia plane relative to the axis of the cylinder thereby to preclude anysubstantial relative movement between a sheet registered and aligned onthe abutment means irrespective of the rotational speed of the cylinder.

6. A sheet handling machine according to claim 5, in which the meansoperable to elfect opening of the grippers at said first position of therockable unit comprise a cam surface provided externally of thecylinder, a bell crank lever pivotally mounted on the cylinder, a camfollower mounted on one end of the bell crank lever and spring meansbiasing the cam follower in a sense away from the axis of the cylinder,whereby during engagement of said follower with said cam surface, thebell crank lever is rocked and the end thereof remote from said followerengages said lever member mounted on the second shaft References Citedin the file of this patent UNITED STATES PATENTS 579,832 Krayer Mar. 30,1897 976,255 Elsas Nov. 22, 1910 2,391,892 Garassino Jan. 1, 1946

